Weft looping means for loom



April 21, 1959 PURDY 2,882,932

WEF'T LOOPING MEANS FOR LOOM Filed Nov. 17,- 1955 2 Sheets-Sheet 1 INVENTOR @mm/ M.

ATTORNEY United States Patent 2,882,932 I WEFT LOOPING MEANS FOR LOOM Bruce B. Purdy, Appleton, Wis. Application November 17, 1955, Serial No. 547,364 9 Claims. (Cl; 139-195) This invention relates to looms and the forming of loops in the weft along the warp edge, and it more specifically resides in an apparatus having a pin mounted adjacent the warp edge to have weft threads looped thereabout and movable in a direction longitudinal of the weft threads, there being a bias urging the pin outwardly from the warp edge such that upon looping a weft about the pin and drawing it through the shed the pin is moved against the bias toward the warp edge, and there further being provided means responsive to pin movement for providing an indication that manipulation of the weft has been properly performed.

It has been a common practice in weaving to form loops in the weft at the warp edge by placing a pin, or the like, adjacent the warp and drawing the Weft about the pin. One of the principal purposes of forming such loopsis to relieve the warp from strain as the weft is tensioned, and to transfer the strain to the more rigid structure provided by the pin. The pin further functions to hold the weft out of and to the rear of the nip of the shed. Weft that is held away from the shed nip will not become wedged in the crossed warp threads and proper tensioning can then be had along the entire length of the weft. Also, one of the causes of breakage is eliminated.

In the present invention a pin is employed for the foregoing purposes and also to play an important test function for determining whether the loop is correctly formed and the weft tensioned before a beat of the lay is made. At times the weft may not pass about the pin, and occasionally weft threads will part in the shed. The occurrence of these faults is detected in the present invention through a novel pin mounting whereby pin movement plays an important part in testing the weaving operation. The pin is biased to move outwardly from the warp edge, and as a weft is tensioned in the shed the pin will be moved inwardly if a proper loop is being formed and there is no breakage of the weft. Movements of the pin are detected, and in the event of improper pin position the loom may be brought to a halt to permit an operator to correct the fault.

It is an object of this invention to provide an apparatus for forming loops in weft threads at the warp edge.

It is another object of this invention to provide an apparatus for forming loops in weft threads that supervises loom operation, to cause loom shutdown in the event of a lack of proper formation of weft loops.

It is another object of this invention to provide an apparatus in which both the forming of a loop in the weft and the tensioning of the weft in the shed is supervised, whereby loom shutdown occurs if either event is not properly executed.

It is another object of this invention to provide apparatus for testing the weft loop forming operation that may be readily incorporated in existing supervisory. control systems for looms.

These and other objects and advantages of this invention will appear in the description to follow. In the 2,882,932 Patent ed Apr. 21, 1959 descriptionw-reference is made to the accompany draw- Fig. 1 is a planview of portions of a loom in which there-is shown apparatus of the invention,

Fig. 2 is a side view in elevation of apparatus in Fig.

l on an enlarged scale viewed through the plane 22,

,Fig. 3' is a -fragmentary plan view of portions of the apparatus in Fig. 1,

Fig. 4 is a fragmentary view in elevation of portions of the apparatus viewed through the plane 4-4 shown in Fig. 1,

Fig. 5 is a fragmentary view in elevation of portions of the apparatus showing bearing engagement betweena mounting bracket for a portion of the apparatus and the edge of the woven cloth, and

Fig. 6 is a schematic wiring diagram forvthe invention.

Referring now to the drawings, there is shown in Fig. 1 the right and left hand ends of a breast beam 1 over which passes Woven cloth 2. The beat line is indicated by the numeral 3 and extending rearwardly from the beat line 3 is a plurality of warp threads 4 which form a right handwarp edge 5 and a left hand warp edge 5'. j A lay 6 is shown disposed at a distance behind the beat line 3, as it is swinging forwardlyin a beat motion. The lay 6 includes a lay cap 7 and a lay bottom 8 between which is disposed the reed 9, all of whichare shown in Fig. 2. In Fig. 2 the lay 6 is in the beat position with the reed 9 at the beat line 3.

At the, right hand side of Fig. 1 there is shown a portion of a' shuttle 10 that is housed within a shuttle box 11. A pirn 12-is shown within the shuttle 10, which carries a supply of weft thread 13. The shuttle 10 has passed from the left hand side of the loom to the right hand side and in doing so trailed the weft thread 13 through the shed. The lay 6 is advancing to beat up the weft 13, and as a preliminary step to the beat, the weft 13 has been tensioned by apparatus now to be described.

A mounting platform 14 is secured to the front side of the shuttle box 11 and secured .to this platform 14 is a bracket 15. Mounted on the outer end of the bracket 15 is an air operated piston actuator 16 from which extend's a piston shaft17. The shaft 17 is connected to one end of a link 18, which is connected at its opposite end to a pivotally mounted block 19. The block 19 supports a stretch-off arm 20 having a spool21 at its extended end. 'Ihus, upon actuation of the piston shaft 17 the stretch-off arm 20 is moved between the position shown in full lines in Fig. 1 and the rear position shown by dotted lines, the normal position being that of the dotted lines.

The operation of the stretch-off arm 20 is in accord-' ance with usual practices. After the shuttle 10 has drawn the weft 13 through the shed, from the left hand side of the loom to the right hand side, the actuator 16 is operated to move the arm 20 from its rear position forwardly to that shown in Fig. 1. As the arm 20 is moved forwardly the spool 21 engages and carries the Weft 13 forwardly to tension it within the shed. A

supplementary spool 22 is mounted on the platform 14 .to be engaged by the weft 13 for accommodating the forward movement. The operation of the arm 20 is usually independent of the operation of the lay 6, but is coordinated therewith for optimum efiiciency.

Referring now specifically to Fig. 4, there is shown mounted on the underside of the bracket 15 a switch 23 ;having a set of stationary contacts 24 and 25. A movable contact 26 is disposed between the contacts 24, 25 and mounted upon the movable contact 26 is a depending arm 27 carrying a roller 28 that fits within a track 29 on a block 30 connected to the piston shaft 17. With the stretch-off arm 20 in the retracted position, shown by the dotted lines in Fig. 1, the movable contact 26 is held in engagement with the stationary contact 24, and upon movement of the stretch-off arm 20 to the position shown by full lines in Fig. 1 the movable contact 26 will have been moved upwardly into engagement with stationary contact 25. In the event that the stretch-off arm 20 be moved farther forward than the position shown in Fig. 1, due to some mishap such as breakage of the weft 13, the movable contact 26 will have again been moved downwardly into engagement with stationary contact 24. Thus, there is provided means for indicating the position of the stretchofi arm 20, that may form a part of a supervisory contral circuit for the loom.

On the left hand side of the lay 6 there is provided a shuttle box and stretch-01f mechanism similar to that described in connection with the right hand side, with the exception of inversion of parts. Similar parts have been designated on the left hand side by designating reference numerals like those used in conjunction with the mechanism on the right hand side of the loom, with the addition of a prime mark.

Referring again to the right hand side of the loom, there is shown mounted upon the breast beam 1 a pair of mounting ears 31 between which extends a shaft 32. Secured to the shaft 32 is an obliquely extending mounting bracket 33 and urging the shaft 32 and its bracket 33 inwardly, or to the left as shown in Fig. l, is a spring 34.

A pair of shaft supporting ears 35 are disposed at the forwardly end of the bracket 33 with a shaft 36 extended therebetween. Mounted on the shaft 36 for pivotal movement in a vertical plane is a channel shaped arm 37, shown more clearly in Figs. 2 and 3, that has a pivot pin 38 carrying a lever 39 from which extends an elongated pin 40 having an end 41 that is disposable immediately adjacent the warp edge 5. The pin end 41, when disposed adjacent the warp edge 5, is in a position such that the weft thread 13 may be looped thereabout. The pin end 41 may be raised from the position adjacent the warp edge by an upward pivot of the arm 37 about the shaft 36 to a position well above the warp edge 5, as is shown in Fig. 2.

Besides the vertical movements that maybe performed by the pin end 41, pivotal movement longitudinally of weft thread 13 in the cloth 2 may also be imparted to the pin end 41 by a swinging movement of the lever 39 about the pivot pin 38. In this manner the pin end 41 may be moved outwardly away from and returned inwardly toward the warp edge 5.

A spring 42, shown in Fig. 3, has one end bearing against the lever 39, and the opposite end bears against an adjustment bolt 43 threadedly received by a bracket 44 extending from the arm 37. The spring 42 presents a bias urging the lever 39 to move outwardly away from the warp edge 5. The movement of the pin end 41 in response to the biasing force of the spring 42 is not great, since the forward end of the lever 39 is brought up against a stop 45 secured to the arm 37, upon a short pivotal swing of the lever 39.

Extending from the forward end of the lever 39 is a switch actuator 46, and mounted upon the bracket 33 is a precision switch 47 with its actuator positioned so as to be struck by the actuator 46. The precision switch 47 is provided with a movable contact 48 and stationary contacts 49 and 50 between which the movable contact reciprocates, all of which are shown in Fig. 6. The movable contact 48- is normally engaged with contact 49, and upon the actuator of switch 47 being moved by the switch actuator 46 the contact 48 is engaged with the contact 50.

'A support 51', adjacent an car 35, rises upwardly from the forward edge of the bracket 33 and extending rearwardly from the upper end of the support 51 is a bracket 52. A guide 53 is mounted at the rear end of the bracket 52, and extended through the guide 53 is a rod 54 that mounts a wheel 55 at its rear terminus. The wheel 55 is in such position as to be struck by the lay cap 7 upon a movement of the lay 6 toward the beat line 3. Upon the lay cap 7 striking the wheel 55 the rod 54 is moved forwardly and its forward end, which is pinned to a lever 56, causes a rotation of the arm 37, the arm 37 and the lever 56 being joined to rotate in unison about the shaft 36. Thus, a forward swing of the lay 6 causes the lever 39 to be raised upwardly and forwardly in an upwardly swinging movement so as to remove the pin end 41 from the position adjacent the warp edge 5 at the beat line 3, where it would-otherwise be struck by the lay 6 as the beat of the weft is carried out. The rod 54 and lever 39 are shown in Fig. 2 in the position to which they are moved by action of the lay 6. The normal positions, assumed upon the lay 6 being retracted, are shown by dotted lines.

A spring 57 encircles the rod 54 and rests at its rearward end against a collar 58 which is fixed upon the rod 54. At the opposite end the spring 57 engages a second collar 59, which moves along the rod 54. When the rod 54 is moved forwardly, in response to forward motion of the lay 6, the spring 57 is contracted, and upon a subsequent retraction of the lay 6' the spring 57 will act to quickly move the rod 54 rearwardly. Hence, the arm 37, lever 39 and pin 40 are quickly moved downwardly so that the pin end 41 will assume its position adjacent the beat line 5. To restrict the downward movement of the arm 37 and lever 39 the mounting bracket 33 is so shaped so as to form a stop against which the underside of the arm 37 rests.

To retain the pin end 41 in proper alignment with respect to the work edge 5, a plate 81 is secured to the bracket 33 and extended beneath the edge of the woven cloth, as is shown in Fig. 5. A rib 82 extends upwardly from the plate 81 to bear against the edge of the cloth, bearing engagement being retained by reason of the bias force of the spring 34. The rib 82 and the pin end 41 are related in such fashion that with the rib 82 bearing against the cloth edge the pin end 41 will be adjacent the warp edge 5.

On the left hand side of the breast beam 1 there is apparatus similar to that which has been described as being mounted on the right hand side, with the exception of inversion of parts. This apparatus on the left hand side has been designated by reference numerals, in Figs. 1 and 6, identical to those used in conjunction with the right hand apparatus, with the addition of a prime mark.

Referred now to Fig. 6, there is shown a drive motor 60 that acts a prime mover for the loom. The motor 60 has an output shaft 61 connected through an electrically operable clutch 62 to a drive shaft 63. The clutch 62 is controlled through a control circuit network 64, which is shown in block diagram form and may take one of several known network configurations. Power lines 65 and 66 feed the circuit network 64 through leads 67 and 68 respectively. The network 64 is responsive to a relay 69 having normally open contacts 79 and 71 operable by a coil 72. The contacts 70 are disposed between the power line 66 and the network 64. The contacts 71 are disposed between the power line 66 and one side of the coil 72. This side of the coil 72 is also joined through a reset button 73 to the line 66. The side of the coil 72 opposite the side joined to contacts 71 is connected to a lead '74. The lead 74 extends to one side of the normally closed contacts, not shown, of a testing switch 75 having an actuator 76 that is operated prior to each beat of the lay 6 to open the switch contacts. In the embodiment of the invention being described the actuator 76 is in the path of a cam'member 77 mounted on apart of the lay 6.

Thus, as the lay 6 moves forwardly for a beat the testing switch 75 is actuated for a brief interval to the contact open position. This is done'at a time when it is desired to test the position of the stretch-01f arms 20, 20 and the pins 40, 40.

The side of the testing switch 75 opposite the lead 74 is joined to the power line 65, thus during the period of closure of the testing switch 75 the relay coil 72 is joined direct to th e line 65. Thus, if the reset button 73 be depressed momentarily, while the testing switch 75 is closed, the coil 72 will be energized and closure of contact 71 will retain the coil 72 energized after release of the button 73. Closure of the contacts 70 is such as to influence the network 64 in a manner that upon a reopening of the contacts 70 the network 64 will act to disengage the clutch 62 and thereby halt the weaving operation.

The switch 23, operable by the piston actuator 16 and indicative of the position of the stretch-off arm 20, has its movable contact 26 connected through a lead 78 to the power line 65. The stationary contact 25 of the switch 23, which is normally open, is connected to a normally engaged contact 49 of the precision switch 47. The normally engaged stationary contact 24 of the switch 23 is in turn connected to the normally open stationary contact 50 of the precision switch 47. The movable contact 48 of precision switch 47 is connected through a lead 79 to the similar movable contact 48 of the precision switch 47'. Normally open stationary contact 50 is connected to normally engaged stationary contact 24' of the switch 23, and the normally engaged stationary contact 49' is connected to normally open stationary contact 25 of the switch 23'. The movable contact 26 of the switch 23' is in turn joined through a lead 80 to the lead 74.

With the lay 6 in retracted position each of the levers 39, 39' is in its lowered position, such that the pin ends 41, 41 are adjacent the warp edges 5, at the beat line 3. The bias of the springs 42, 42 will move the pin ends 41, 41 outwardly so as to be slightly spaced from the warp edges 5, 5'. If the shuttle is now passed through the shed from the left hand side to the right hand side, so as to come to rest in the position shown in Fig. l, the weft thread 13 will be passed around the pin end 41' and threaded through the shed.

The stretch-off arm 20 is now actuated through the piston actuator 16, to engage the weft 13 and draw it through the shed to tension the weft 13 and to form a loop about the pin end 41. Also, the lay 6 is moved forwardly in a beat motion. The action of the arm 20 produces sufiicient tension in the weft to form a tight loop about the pin end 41 that causes movement of the lever 39' against the bias spring 42'. The resulting motion of the lever 39' actuates the switch 47 to place the movable contact 48 in engagement with the stationary contact 50'. If the stretch-off arm 20 gathers the weft 13 and tensions it correctly the switch 23 will have its movable contact 26 move into engagement with the stationary contact 25. It is at this time that the contacts of the testing switch 75 are opened. Continued energization of the relay coil 72 is dependent upon both an operation of the switch 23 and of the switch 47', and in the event these switches 23, 47 are not correctly operated the coil 72 is deenergized to open contacts 70 and 71. Opening of contacts 70 influences circuit 64 to operate clutch 62 for disengaging the motor 61 from the shaft 63, thereby bringing the weaving operation to a halt. In this manner the continuation of weaving is dependent upon the forming of a correct loop in the weft, at the warp edge, and in stretching the weft through the shed by drawing it a predetermined distance by a stretch-01f arm. The test of weft manipulation ceases upon the contacts of the testing switch 75 reclosing. If the test is satisfactory the lay 6 continues its beat motion and strikes the wheels 55, 55 whereby the pins 40, 40' areraised upwardly and forwardly.

Upon retraction of the lay 6 the pins 40, 40 are returned to positions adjacent the warp edges 5, 5'. The

shuttle 10 will be propelled from the right hand box 11' to the left hand box 11, and weft 13 will be looped about pin end 41. The stretch-off arm 20' will be actuated and the lay 6 moved forwardly to beat the weft I3. Tensioning of the weft 13 must move the pin end 41 inwardly to close contact 50, and the movement of the arm 20' must be such' as to close contact25'. 1*hen','as"thetesting switch 75 is opened weaving will continue if correct weft manipulation has been had.

If the weft 13 parts in the shed, orif it is not engaged and tensioned either the respective stretch-off arm 20,- 20 will advance forwardly beyond the position of closure of the respective contact 25, 25' or the lever being used to form a weft loop will not move to operate the respec-.

tive switch 47 or 47'. Also, if a loop of weft is not formed at the warp edge about a pin end the particular switch 47, 47 will not'be operated to close-its contact 50, 50'. In either event loom stoppage-occurs,;in re sponse to the indication of an improper function by the test circuit network.

It is to be noted that when the weft thread is tensioned in the shed by action of a stretch-01f arm 20, 20 that the weft is looped about one of the pin ends 41 or 41 and held from the nip of the shed by the other pin end, 41' or 41, by reason of the weft passing to the rear of such' pin end, as shown in Fig, 1 with respect to pin end '41. Weft breakage is minimized by this action of the appara tus. The direction of force upon the pin end which the weft turns about, as distinguished from being looped about, is such that the pin end is not moved to actuate its corresponding switch, 47 or 47', during tensioning, and therefore such pin end does not interfere with tests made upon opening the switch 75.

The invention provides for forming a weft loop, and then tests the operation of the apparatus to determine whether proper manipulation of the weft has taken place. The test of the operation is carried out at both ends of the weft to be beat, and a proper test insures continuity of the weft through the entire shed. If the supervisory control indicates proper operation the' loom is permitted to proceed, otherwise it is halted. The invention may be employed with apparatus that provides a very rapid stoppage of the loom, before a beat and heddle change is completed, thereby permitting curing of a fault before irreparable damage occurs in the woven cloth.

I claim: a

1. In weft loop forming apparatus for a loom the combination comprising a bracket slidable toward and away from the warp edge having a bearing member adapted to rest against the warp edge; means urging the bracket. and its bearing member against the warp edge; a pin carried by the bracket to be positioned adjacent the warp edge and movable longitudinally of weft threads toward and away. from the edge; said pin being disposed to be looped by a weft and moved toward the warp edge upon tensioning the weft; a bias urging the pin away from the warp edge; and means responsive to pin movement to be indi cative of pin position.

2. In weft loop forming apparatus for a loom having warp and weft threads the combination comprising a bracket slidable toward and away from a warp-edge having a member adapted to engage the warp edge and be positioned thereby; means urging the bracket toward engagement with thewarp edge; a lever which includes a pin to be disposed alongside the warp edge; an arm carried by said bracket, which arm mounts said lever and is movable to carry the lever into the position having the pin alongside the warp edge and away "from such position to remove the pin from alongside the warp edge; said lever being mounted upon said arm fora movement that carries the pin in a direction longitudinal of the weft threads; a bias urging the lever to move in a direction that moves the pin outwardly from the warp edge; actuating means for raising and lowering said armin'timed relation to movement of the loom lay; and stationary switch means on said bracket having an operator cooperatively engageable with said lever when said lever is in position to have the pin alongside the warp edge, which switch means has contacts opened and closed in response to inwardand outward movement of the lever whereby the position of the contacts is indicative of pin position.

3 In weft loop forming apparatus for a loom having warp and weft threads the combination comprising a bracket slidable toward and away from a warp edge having amember adapted to engage the warp edge and be positioned thereby; means urging the bracket toward engagement with the warp edge; a lever which includes a pin end to be placed in a vertical position alongside the warp edge at the beat line whereby a weft laid in the shed will loop about the pin end; an arm carried by said bracket, which arm mounts said lever and is movable for raising and lowering the pin end from the position alongside the warp edge, said lever being mounted upon said arm for a reciprocal movement that carries the pin end outwardly from and inwardly toward the warp edge; a bias urging the lever to move in a direction that moves the pin end outwardly from the warp edge, which bias is overcome by tensioning a weft looped about the pin end; actuating means for raising and lowering said arm in timed relation to the loom; and means on said bracket cooperatively operable with said lever when said lever is alongside the warp edge to be responsive to lever movements and thereby indicative of pin end position.

4.. In weft loop forming apparatus for a loom having warp and weft threads the combination comprising a bracket slidable toward and away from a warp edge having a member adapted to engage the warp edge and be positioned thereby; means urging the bracket toward engagement with the warp edge; a lever which includes a pin end to be placed in a vertical position alongside the warp edge at the beat line whereby a succeeding insertion of weft in the shed will loop the weft about the pin end; an arm carried by said bracket, which arm mounts said lever and is fulcrumed for movement that carries the levertand hence the pin end in reciprocal movements upwardly from and downwardly to the position alongside the warp edge, said lever being pivotally mounted upon said arm for reciprocal movement that carries the pin end in a direction outwardly from an inwardly toward the warp edge; a bias urging the lever to move in a direction that moves the pin end outwardly from the warp edge; actuating means for raising and lowering said arm in timed relation to movement of the loom lay; switch means mounted on said bracket beside said arm to be relatively stationary with respect to the arm, said switch means being cooperatively engaged with said lever and having contacts opened and closed in response to movement of the lever, with respect to said arm, whereby the position of the contacts is indicative of pin end position; and a circuit network including said contacts and means for interrupting loom operation whereby a failure of a weft to loop about the pin end and move the lever against said bias will cause said contacts to assume a position that causes cessation of weaving.

5. In weft loop forming apparatus for a loom the com bination of a power drive for the loom; a circuit network controlling the power drive which includes switch means having a coil and contacts operable thereby, which switch means has a contact position that halts the loom; a base movable transversely of warp threads; a bias urging the base inwardly of the loom towards such warp threads; an arm on the base movable vertically with respect to the plane of the warp threads; a lever which includes a pin mounted on the arm to be disposed alongside a warp edge to have a weft thread looped thereabout, said pin being mounted fora movement outward from and inward towardv the warp edge whereby a weft looped thereabout and tensioned moves the pin toward the warp edge; a bias urging said pin outwardly from the warp edge; a

switch mounted on the, base having an operator with which a portion of the lever aligns when the arm is in lower position to place the pin alongside the warp edge, which switch is responsive to said pin and indicative of pin position; a testing switch opened and closed in timed relation to loom operation to provide a testing interval; and connections joining both said testing switch and said switch through alternative current paths with said switch means coils, whereby a pin position outward from the warp edge during the test interval will cause said switch means to halt the loom.

6. In weft loop forming apparatus for a loom the combination of a power drive for the loom; a circuit network controlling the power drive which includes switch means having a position permitting maintenance of loom operation and operable to cause said network to halt loom operation; weft tensioning means including a first switch operable thereby indicative of proper tensioning of a weft; a lever which includes a pin disposable alongside the warp edge to have a weft thread looped thereabout, said lever being mounted for a movement of the pin in a direction longitudinal of weft threads; a bias urging said lever in a direction to move the pin outwardly from the warp edge which bias may be overcome by tensioning a weft looped about said pin; a second switch cooperatively engaged with said lever with con- 'tacts movable in response to lever movement to be thereby indicative of lever position; a testing switch opened and closed in timed relation to loom operation to provide periodic testing intervals; and connections joining said testing switch with said first and second switches to provide an energizing circuit for said switch means whereby said weft tensioning means and lever must each be in predetermined position during a testing interval of the testing switch to retain said switch means in position for maintaining loom operation, and whereby an alternative position for either said first and second switches during such an interval causes operation of said switch means to cause said network to halt loom operation.

7. In weft loop forming apparatus for a loom the combination comprising a mounting bracket movable toward and away from a warp edge which includes a stop adapted to bear against such warp edge; a bias urging the bracket and its stop against the warp edge; an arm mounted on the bracket movable upwardly and downwardly; a lever pivoted on the arm with a pin at one end which is movable longitudinally with respect to the weft threads and adapted to be placed alongside the warp edge when the arm is in one of its positions; bias means interposed between the arm and the lever to urge the pin outwardly from the warp edge; stop means on the arm limiting movement of the lever in response to the bias means; and means mounted on the bracket that is responsive to lever position in its longitudinal movement with respect to the weft threads.

8. In weft loop forming apparatus for a loom the combination comprising a bracket movable transversely of warp threads; a bias urging the bracket inwardly of the loom toward such warp threads; an arm mounted on the bracket movable upwardly and downwardly; a lever pivoted on the arm with a pin at one end which is movable longitudinally with respect to the weft threads and adapted to be placed alongside the warp edge when the arm is in one of its positions; bias means interposed between the arm and the lever to urge the pin outwardly from the warp edge; stop means on the arm limiting movement of the lever in response to the bias means; and means mounted on the bracket that is responsive to lever position in its longitudinal movement with respect to the weft threads.

9. In a weft loop forming apparatus for a loom the combination of weft tensioning means including a first switch operable thereby indicative of proper tensioning of a weft; a lever which includes a pin disposable alongside the warp edge to have a weft thread looped there- 9 about, said lever being mounted for a movement of the pin in a direction longitudinal of weft threads; a bias urging said lever in a direction to move the pin outwardly from the warp edge which bias may be overcome by tensioning a weft looped about said pin; a second switch cooperatively engaged with said lever with contacts movable in response to lever movement to be thereby indicative of lever position; a testing switch opened and closed in timed relation to loom operation to provide periodic testing intervals; current responsive means; and connections joining said testing switch with said first and second switches and said current responsive means to provide a test circuit whereby said weft tensioning means and lever must each be in predetermined position during 10 a testing interval of the testing switch to have a circuit condition for the current responsive means indicative of proper operation.

References Cited in the file of this patent UNITED STATES PATENTS 2,232,630 Payne Feb. 18, 1941 2,638,942 Hindle May 19, 1953 2,646,827 Cederlund July 28, 1953 FOREIGN PATENTS 553,260 Germany June 23, 1932 1,040,684 France May 27, 1953 

